The increasing use of wireless telephones and personal computers by the general population has led to a corresponding demand for advanced telecommunication services that were once thought to only be meant for use in specialized applications.
For example, in the late 1980's, wireless voice communication such as available with cellular telephony was the exclusive province of the businessman because of relatively high subscriber costs. The same was also true for access to remotely distributed computer networks, whereby until very recently, only business people and large institutions could afford the necessary expensive equipment to access computer networks.
However, the general population now increasingly wishes to not only have access to computer networks such as the Internet and private intranets, but also to have access to such networks in a wireless fashion as well. This is particularly of concern for the users of portable computers, laptop computers, hand-held personal digital assistants, and the like, who would prefer to access such networks without being tethered to a telephone line. There still is no widely available satisfactory solution for providing low cost, high speed access to the Internet and other computer networks using the existing wireless telephone systems such as cellular. This unfortunate situation is most likely an artifact of several circumstances. For example, the typical manner of providing high speed data service in the business environment over the wireline network is not readily adaptable to the voice grade service available in most homes or offices. Such standard high speed data services therefore do not lend themselves well to efficient transmission over standard cellular wireless handsets.
Furthermore, existing cellular network was originally designed only to deliver voice services. At present, the modulation schemes in use continue their focus on delivering voice information with the maximum data rate services in the range of only 9.6 kbps being available. This is because the cellular switching network in most countries, including the United States, uses analog voice channels having a bandwidth from about 300 to 3600 Hertz. Such a low frequency channel does not lend itself directly to transmitting data at rates of 28.8 kilobits per second (kbps) or even 56.6 kbps that is now commonly available using inexpensive wire line modems, and which rates are now thought to be the minimum acceptable data rates for Internet access.
Switching networks with higher speed building blocks are just now coming into use in the United States. Although certain wireline networks, called Integrated Services Digital Networks (ISDN), capable of higher speed data access have been known for a number of years, their costs have only been recently reduced to the point where they are attractive to the residential customer, even for wireline service. Although such networks were known at the time that cellular systems were originally deployed, for the most part, there is no provision for providing ISDN-grade data services over cellular network topologies.